Automatic circuit breaker



June 30, 1931. J, SACHS AUTOMATIC CIRCUIT BREAKER Filed May 25, 1929 2"SheetsSheet l June 30, k1931. J, SACHS 1,812,848

AUTOMATIC CIRCUIT BREAKER `FiledMaLy 23, 1929 2 Sheets-Sheet 2 [UVENUF Patented `lune 30, 193i PATENT GFFICE JOSEPH SACHS, F WEST HARTFORD, CONNECTICUT AUTMATIC CIRCUIT BREAKER Application led May 23,

rlhis invention relates particularly to an automatic circuit breaker of the type set forth in my copending applications for automatic circuit breakers, Serial No. 271,819,

',iled April 21, 1928, Serial No. 283,060, led June 5, 1928, and Serial No. 382,924, lled January 16, 1929.

The general object ofthe invention is to provide a circuit breaker of the type referred lo to having various improved details whereby h attain greater economy of manufacture, greater reliability of operation, improved arc extinguishing characteristics and e'ect other desirable results.

ln the accompanying drawings l have shown the embodiment of the invention which I now deem preferable, but it will be understood that the drawings are intended for illustrative purposes only and are not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawings:

Fig. 1 is a side view of a circuit breaker embodying the invention, the movable parts being shown in their closed-circuit positions and the base and the enclosing cover being shown in section as indicated by the line 1-1 of Fig. 6.

Fig. 2 is a transverse vertical sectional view taken along the line 2--2 of Fig. 6 and showing the movable parts in their open-circuit position..

Fig. 3 is a side view similar to Fig. 1 but showing the circuit breaker unit without the cover and base, and showing the parts in the positions which they assume when the circuit is broken automatically with the handle held in its closed-circuit position.

Fig, 4 is a front-view with the enclosing cover shown in section along the line 4-4' of Fig. 1. Y

Fig. 5 is a vertical sectional view taken along the line 5-5 `of Fig. 1, the enclosing cover being omitted.

Fig. 6 is a horizontal sectional View taken looking upward along the line 6 6 of Fig. 1.

Fig. 7 is a side view similar to Fig. 1 but 59 showing the contacts in their position of first i929. Serial No. 365,419..

engagement just before they reach their normal contacting positions.

Fig. 8 is a detailed perspective view showing the more important elements of the circuit breaker separated from each other in order that the details of construction may be more clearly understood. rllhe parts are Iin relative positions corresponding approximately to those shown in Fig. 3.

Referring to the drawings, it will be observed that the main body of the circuit breaker unit comprises two parallel spaced sides plates 1, 1 connectible with a rear support and adapted to project forward therefrom. ln accordance with one phase of the invention these side plates are metallic, and they are preferably electrically insulated from each other so as to be adapted to form parts of the electric circuit. The said plates 1, 1, whether insulated from each other or not, are preferably formed at the rear with integral supporting flanges 2, 2 positioned perpendicularly to the main portions thereof and directly connectible to a rear support.

The rear support may be variously constructed, but as shown it is a base 3 of insulating material, to which the supporting flanges 2, 2 are connected by means of screws y* 4, 4. Preferably the base carries conducting strips 5 and 6 provided respectively with wire terminals at 7 and 8. The two flanges 2, 2 engage respectively with the said conducting strips 5 and 6 and thus the plates 1, 1 are electrically connected with the circuit terminals. The base 3 may be provided with wire holes 7 a and 8a adjacent the respective terminals 7 and 8.

I provide a contact member which is pivotally mounted with respect to the body, that is, with respect to the side plates 1, 1. The contact member includes two side plates 9, 9 which are pivotally mounted for movement about a transverse axis. For this purpose there is provided a transverse rod 10 supported at its ends upon the side plates 1, 1 of the body, the ends of the rod being reduced in diameter and extending through insulating members 11, l11 located in holes in the plates. Nuts 12, 12 are provided at the ends of the rod, 10, these being separated from the plates 1, 1 by means of insulating washers 13, 13. The side plates 9, 9 are connected with each other by means of a tie rod 14 connected therewith by means of screws 14a, 14a,

and are also otherwise connected as will presently appear.

Suitable electric contacts are provided, there "preferably being two stationary contacts 15, 15 carried by the body of the circuit breaker and two movable contacts 16,

. 16 carried by the contact member and adaptstrip 17 bent in S-shape as shown in Fig. 1,

y clearly in Fig. 8. Each of the aforesaid openl and having the contact face thereof located in al plane approximately parallel to the pivotal axis of the Contact member, and at an angle to the direction of movement of the contacts. Each contact strip is provided with an ear 17a in a vertical plane and held in engagement with the corresponding side plate 1 by means of a screw 18.

The movable electrical contacts 16, 16 pIO- ject laterally from the side plates 9, 9 of' the contact member and are adapted to engage the stationary contacts 15, 15 as shown in Fig. 1, the said contacts engaging each .other over 'their entire flat contact faces.

Extending transversely between the two side plates 9, 9'is an insulating bar 19 and the two contacts 16, 16 are extended inward as shown at V20, through suitable'openings 21, 21 in the side plates so as to engage the bar 19 at the lower face thereof as shown most ings -21, 21 in the side plates 9,9 is shaped as shown in Fig. 8, each opening having a relatively wide portion and a relatively narrow portion. The wider portion ofeach opening is of sufficient width to permit the corresponding contact 16 to be moved therethrough. Each contact 16 is notched at 16a, 16, the portion thereof between the notches being of such width being adapted to enter and lit the narrower portion of the corresponding opening 21.v When the two contact ymembers have been put in place as describedwith the narrower portions thereof entered at the narrower portions of the openings 21, 21, the transverse insulating bar 19 is put in place with the ends thereof extending into and filling the wider portions of the openings 21,21. The portions 20, 20

of the contact members are then connected with the transverse insulating bar 19 by means of screws 22, 22. Thus, the transverse insulatingv bar by extending" into` the openings 21, 21 serves to lock the contact members in place in the narrower parts of the openings, and it also serves indirectly, by reason of its connection with the contact members,

to assist in holding the plates 9, 9, in their proper spaced relation. m

The entire contact member is biased toward its lower circuit position as shown in Figs. 2 and 3 by means of a coil spring 23 surrounding the pivot rod 10.

There is provided a movable member 24 which I will term an actuator, this member serving as the means for moving or actuating the contact member for normal swltching purposes or to effect closin of the circuit after automatic opening t ereof. The actuator 24 is pivotally movable about the same axis as the contact member, preferably being mounted on the pivot rod' 10 between the side plates. The actuator 24 is shown as being made of sheet metal bent to form two side members 2,5, 25 connected by integral cross members 25a, 25". The side members 25, 25 are'apertured to receive the pivot rod 10. This actuator is adapted to be manually operated in the manner to be presently described.

I provide an electro-responsively releasable mechanical connection between the actuator and the contact member, which connection is operative to enable the actuator to 5 operate the contact member for ordinary switching purposes and which is automatically released upon the passage of excess cur rent so as to permit the contact member to then automatically move independently of n the actuator to its open-circuit position. I prefer and have shown for this purpose an electro-responsive bi-metallic thermal strip 26 which is adapted to be deflected by reason of the heating action of excess current therein in accordance with the well known action of such bi-m'etallic'strips. 'Thesstrip 26 is substantially U-shaped, and has the legs thereof connected respectively by means of screws 27, 27 with extensions 20a, 20l on the movable 110 contact members. f It will be observed that the strip 26 provides an electrical connection between the two movable contacts 16, 16, thus, when the movable and ixed contacts are in engagement, completing the circuit through the entire unit.

The said strip 26 is so shaped `and positioned that it serves in and of itself as a latch to hold the contact member and the actuator 24 in normally fixed relationship with each 1m other. For this purpose the two side members 25, 25 of the actuator carry a transverse pin 28 on which is mounted a rotatable roller 29. The thermal strip 26 carries a pin 30 which projects transversely and which is adapted to normally engage the roller 29. as clearly shown in Figs. 1 and 2. As shown, the pin 30v projects inward with respect to its path of arcuate movement. At normal tems peratures the strip 26 servers to mechanically 130 teiasas connect the contact member and the actuator 2l, but when the bil-metallic strip is heated by reason of the passa-ge of excess current therethrough it is deflected outward as shown by dot-and-dash lines in llig.. 1,v so as to cause the pin 30 to disengage the roller 29 and permit the contact member to move under the induence of the spring 23 in the clockwise direction so as to separate the contacts 13, 16 from' the contacts 15, 15 and thus break the circuit.

The roller 29 and the pin 30 are preferably formed of hardened steel so as to avoid wear. The roller 29 is freely rotatable and friction is thus reduced to a minimum. The thermal strip 26 is thus free to deflect in accordance with the heating action therein without any substantial interference by reason of friction at the point of engagement with the actuator.

F or manually operating the actuator 24, l provide a handle member 31 which is preferably carried directly by the two side plates 1, 1. As shown clearly in Figs. 1 and 4 there is provided a transverse pivot rod 32 upon which the handle member 31 is rotatably mounted, this pivot rod being connected at its ends with the two side plates. It is insu lated at its ends from the corresponding side plates by means of bushings 33, 33 and washers 34, 34, the latter being held in place by nuts 35, 35. The handle is biased for movement i-n the counter-clockwise or circuit opening direction by means of a coil spring 36. Links 37, 37 serve to connect the handle member 31 with the actuator 24, these links being located at the sides Vof the handle meniber and between the side members 25, 25 of the actuator. They are connected with the handle member bymeans of a pivot pin at 38 and they are connected with the actuator by means of a pivot pin at 39.

ll7hen the parts are in the relative positions shown in llig. l the links 37, 37 cooperate with the handle member itself to form a toggle action which locks the parts in position with the movable contacts 16, 16 pressed into lirm engagement with the stationary contacts 15, 15. 'lhe pivotal axis at 38 is at the left of a straight line connecting the pivotal axes at 32 and 39 and thus the handle member and the links 37, 37 serve to resist the tendency of the Contact member to move in the clockwise direction under the influence of the spring 23 and the resilient contact strips 'l 17. .dit the same time the toggle action holds the handle member in its upper closed* circuit position, resisting the tendency of the spring 36 to move it downward. Upward movement of the handle member 31 is limited by reason of the engagement of the entension 31a thereof with the pivot rod 10,

The above described toggle action can be released by pressing the handle downward. the parts then moving under the action of the springs 23 and 36 to the relative positions shown in 2. The movable contacts 16, 13 are thus disengaged from the stationary contacts 15, 15 and the circuit is broken at two separate places. By moving the handle upward the several parts can be restored to their relative positions as shown in Fig. 1 and the circuit can be reestablished. lt will be understood that during operation of the d evice by means of the handle, the pin 30 remains in engagement with the roller 29 and thus the thermal strip 26 serves'as a mechanical connection between the Contact member and the actuator.

As already explained, the thermal strip 26 is adapted to be deflected outward upon the passage of excess current therethrough with the result that the pin 30 is disengaged from the roller29. `When this occurs 'the contact member moves automatically to the position shown in Fig. 3, this movement not being in any way-dependent upon the handle member and the actuator. ln fact the handle member may be held in the position shown in Fig. 3 without in any way interfering with the automatic releasing action. lt will be understood however that, as already explained, the handle is ordinarily held in its closed-circuit position by reason of pressure transmitted through the links 37, 37. As soon as the thermal strip is released from its engagement with the actuator, this pressure through the links 37, 37 is instantly released, and the handle member and the actuator immediately move to their open-circuit positions whereupon the pin 30 is again engaged with the roller 29 as shown in Fig. 2. Movement of the handle member and actuator to their opencircuit positions occurs substantially simultaneously with the movement ofthe contact member. The parts can be restored to their closed-circuit positions as shown in lig. 1 by merely moving the handle member upward.

The movement of the contact `member in the clockwise direction to its open-circuit position, whether effected manually or automatically, is limited by reason of the direct engagement of portions of the plates 9, I9 with a forward facing surface on a rear 4member of the device. This forward facing Surface may be formed on the main rear support, as for instance on the base 3, but as preferred and as shown, the plates 9, 9 engage directly with the forward facing front surfaces of the flanges 2, 2 which are formed on the side plates 11, 1. Portions of the outer edges of the side plates are circularly curved and 16 upon engagement or disengagement contact member have not fully reached their .below their inal contacting position.

closed-circuit positions. The contacts initially engage over their entire Contact surfaces, but they engage at a point slightly To reach their final contacting position, the contact 16 .moves in the direction of the arrow a and the contact moves approximately in the direction of the arrow Z), being guided for movement'in an arcuate path approximately concentric with its point of mounting. The contacts 16 and 15 thus move in directions at an angle to each other with the result that there is a relative sliding or wiping engagement in the direction-of the ar- 'row c, this sliding or wiping action continuing from the time the. position shown in Fig. 7 is reached. until the contacts reach theirvfinal positions as shown in Fig. 1. It will be understood that the action of the contacts is reversed when they are disengaged. This sliding or wiping action during engagement and disengagement is important in preventing corrosion or pitting of the contacts and in otherwise securing-firm electrical connection.

I preferablyv provide adjacent the path of movement of each movable contact 16, a series of stationary metallic pieces 41, 41 insulated from each other and serving to rupture any arc, that may be formed as the movable contact is separated from ,the stationary contact. These conducting metallic pieces being closely adjacent the path of the movable contact member, serve to break up any possible arc so as to form several smaller arcs, the result being that with the voltage for which the circuit breaker is designed the several small arcs in series cannot be maintained and they are automatically extinguished. These metallic pieces 41, 41 are preferablycarried by a downward extending portion of the corresponding insulating member 11. Each of the said members 11 have a convex arcuate face concentric with the arcuate path of movement of the corresponding contact 16 and the metallic pie-ces 41, 41 may be in the form of pins embedded in the extending portion of the member 11 and projecting fxgom the convex arcuate surface thereof.

From the foregoing description it will be I apparent that the side plates 1, 1 and the various parts carried thereby constitute in and of themselves a circuit breaker unit which is entirely self-contained. This unit may be mounted upon a base such as 3 having conductor. members thereon as already described, or it may be. mounted on any suitable base or panel or combinedewith other electrical parts as required. It is only .essential to provide electrical connection to the two main supporting plates 1, 1 which constitute. the electrica-l terminals of vthe unit.

It is usually desirable to provide a cover` for the unit and in order that this cover may be mounted entirely independently of the rear support, I have made provision for connecting it directly with the separable circuit breaker unit independently of the rear support. .As-shown there is a cover 42 and the insulating elements 11, 11 are provided with bosses 43, 48 which extend through suitable holes in the side plates '1, 1. Thesebosses` 43, 43 are provided with threaded holes and screws 44, 44 extend inward through open? ings in the side walls of the cover 42 and are engaged in the said holes in the bosses 43, 43. Thus the cover 42 is connected directly with the circuit breaker unit and is not dependent for its'position upon the rear support.

Vhat I claim is:

1. In an automatic circuit breaker, the combination of a rear support having a forward facing surface, two main side plates spaced apart and projecting forward from the rear member, a contact member pivoted to the main plates for movement about a" Y transverse axis and comprising two spaced plates substantially parallel to the said main plates, the said contact member being biased for automatic movement in one direction and the said plates thereof being formed to directly engage a forward facing surface on the support to limit such movement, two stationary electric contacts, two movable electric contacts on the contact member engageable respectively with the stationary contacts and movable out of such engagement when the contact member is moved automatically gage.

combination oftwo main spaced side plates of conducting material insulated from each other and eonnectible to a rear support, means for connectingthe said side plates with an. electric circuit, a contact member pivoted to the main plates for movement about a transverse axis and biased for automatic movement in one direction, two sta;- tionary electric contacts respectively extendt ing from and electrically connected with the 3. In an automatic circuit breaker, the

vif

temete two side plates, two movable electric con tacts on the contact member engageable re-1 spectively with the stationary contacts and movable out of such engagement when the Contact member is moved automatically as aforesaid, a manually movable actuator, and an electro-responsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latteru el.. A circuit breaker as set forth in claim 3, wherein the side plates have integral supporting ilanges positioned perpendicularly to the main portions thereoitl and connectable to a rear support.

5. A circuit breaker as set forth in claim 3, wherein the actuator is mounted on the main side plates and wherein'the said plates are mechanically connected with each other independently of any support upon which they y may be mounted.

6( A circuit breaker as set forth in claim 3, wherein the actuator is mounted on the main side plates, wherein the electro-responsively controlled mechanical connection is carried entirely by the saidcontact member and actuator, and wherein the side plates are mechanically connected with each other independently of any support upon which they may be mounted, thereby forming a self-contained circuit breaker unit having all of its parts carried by the connected main side plates.

7.. A circuit breaker as set forth in claim 3,

wherein the actuator is pivotally mounted onthe main side plates and wherein the electroresponsively releasable mechanical connection comprises a bi-metallic thermal strip electrically connected between the two movable contacts.

8. A circuit breaker as set forth in claim 8, wherein the actuator is pivotally mounted on the main side .plates and wherein the electroresponsively releasable mechanical connection comprises a bi-metallic thermal strip electrically connected between the two mov.

able contacts, and wherein vthe said strip serves in and of itself as a releasable mechanical latch between the contact member and the actuator.I

9., ln an automatic circuit breaker, the combination oi an insulating base, spaced conductors on the base at the front thereof, two main spaced side plates of conducting material insulated from each other and detachably connectible respectively with the said conductors on the base, a contact member pivoted to the main plates for movement about a transverse axis and biased for automatic movement in one direction, two stationary electric contacts respectively extending from and electrically connected with the two side plates, two movable electric contacts on the contact member engagable respectively with the stationary contacts and movable out of such engagement when the contact member is moved automatically as aforesaid, a manually movable actuator, and an electro-responsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter.,

l0. ln an automatic circuit breaker, the combination of two main spaced `side plates connectible to a rear support, a contact member pivoted to the main plates for movement about a transverse axis and biased for automatic movement in one direction, two stationary electric contacts, two movable electric contacts on the contact member engagable respectively with the stationary contacts and movable out of such engagement when the contact member is moved automatically as aforesaid, a manually movable actuator carried by the main plates, an electro-responsivcly releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter, and an enclosing cover detachably held in place by means of the side plates independently of any rear support to which the side plates may be connected.

ll. ln an automatic circuit breaker, the combination of a main body, a contact member pivoted to the main body for movement about a transverse axis and biased for automatic movement in one direction, a manually movable actuator, an electro-responsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter, two movable electric contacts on the Contact member, two other electric contacts adapted to be engaged and disengaged by the movable contacts when the contact member is moved by the actuator or is moved automatically, the iirst and second-said contacts having contact faces positioned to engage each other in a plane substantially parallel to the pivotal axis ot the contact member and at an angle to the direction of movement of the movable contacts, and means for resiliently supporting the second said contacts and for guiding them 1for limited movement during engagement in a direction at an angle to the direction of movement of the movable contacts, whereby there is obtained a relative wiping action between the said contacts.

12. :ln an automatic circuit breaker, the combination oi' a main body, a contact member pivoted to the main body for movement about a transverse axis and biased 'for automatic movement in one direction, the said contact member comprising two spaced plates of insulating material having similar openings therein each having a relativelywide portion and a relatively narrow portion, a manually movable actuator, an electro-responsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter, two stationary electric contacts, two movable electric contacts carried by the respective side plates of the contact members and extending through the opening therein, the outer operative portion of each contact being wider than the narrower portion of the corresponding T-shaped openings and the intermediateportion of each contact being of such width as to enable it to fit into the said narrower portion of the opening, and a body of insulating material extending transversely between the two plates and entering the wider portions of the openings to hold the contacts in the said narrower portions thereof.

13. In an automatic circuit breaker, the combination of a contact member pivotally mounted for movement about a transverse axis and biased for automatic movement in one direction, va manually movable actuator, an electro-responsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter, two stationary electric contacts at the respective sides of the contact member, two movable electric contacts on the contact member at the sides thereof engageable respectively with the stationary contacts and movable out of such engagement when the contact member is moved automatically as aforesaid, and two series of stationary metallic pieces located at opposite sides of the contact member and closely adjacent the respective paths of movement of the movable contacts, the metallic pieces of each series being insulated from each other so as to serve to break up any arc that may be formed.

14. A circuit breaker asset forth in claim 13, wherein there are bodies of insulating material having convex faces concentric with the arcs of movement of the movable contacts,

and wherein the metallic pieces project radiall outward from the said convex faces.

15. n an automatic circuit breaker, the combination of two main side plates spaced apart, a cont-act member between the main plates and pivoted thereto for movement about a transverse axis, the said member being biased for automatic movement in one.A

direction and comprising two spaced plates substantially parallel to the said main plates,

' a manually movable actuator, an electroresponsively releasable mechanical connection between the actuator and the contact member normally enabling the former to move the latter, two stationary `electric contacts at the respective sides of the contact member, two movable electric contacts on the contact member at the sides thereof engageable respectively with the stationary contacts and movable out of such en agement when the contact member is mov automatically a s aforesaid, and a series of Stationar metal- 11o pieces insulated from each ot erv and carried by the corresponding main side plate,

the pieces of the said series being located closely adjacent the path of movement of the corresponding movable contact so as to serve to break up any arc that may beformed.

16. A circuit breaker as set forth in claim 15, wherein the main side plates are of conducting material, wherein the stationary contacts are carried by and electrically connected with the main side plates, wherein there is a body of insulating material on' one main side plate and having a convex face concentric with the arc of movement of the corresponding movable contact, and wherein the metallic pieces project radially outward from the said convex face.

17.. An automatic circuit breaker comprisin in combination, a contact member pivote for movement about a fixed axis and biased for automatic movement in one direction, an actuator pivoted coaxially with the contact member and including a transverse rotatable roller, astationary electric contact, a movable electric contact on the contact member adapted to engage the stationary contact and movable' out of engagement therewith when the conta'ctmember is moved automatically as aforesaid, and an electroresponsive lthermal strip carried by the contact member and provided with a pin normally engaging the roller of the actuator to serve as a latch toprevent movement of the contact member relatively to the actuator, the said strip being electrically connected with the movable contact and serving upon the passage of excess current to move the pin out of engagement with the roller and thereby permit automatic movement of the contact member to open-circuit position. v

In'testimony whereof I have hereunto set my hand this 21st day of March, 1929.

JOSEPH SACHS 

